[0001] Embodiments of the invention refer to a power line communication apparatus comprising
an AC (alternating current) power socket and a method of operating a power line communication
apparatus.
[0002] Some communications systems like PLC (power line communications) use power distribution
systems for data communication, wherein a modulated carrier is superimposed to the
50 or 60 Hz alternating current of the power lines. For example, a power cable containing
two or more electrical conductors is used for transmission of AC (alternating current)
electric power, wherein the power cable may be installed as permanent wiring within
buildings or may be buried in the ground. Power line communication modems may be plugged
into any outlet of the power distribution system.
[0003] The object of the invention is to increase ease of use of a power line communication
system. The object is achieved with the subject-matter of the independent claims.
Further embodiments are defined in the dependent claims, respectively. Details and
advantages of the invention will become more apparent from the following description
of embodiments in connection with the accompanying drawings. Features of the various
embodiments may be combined unless they exclude each other.
Figure 1 is schematic block diagram of a power line communications system comprising
a power line communication apparatus in accordance with an embodiment of the invention.
Figure 2 is a schematic block diagram showing details of a power line communication
apparatus with a mains filter in accordance with another embodiment of the invention.
Figure 3A is a simplified perspective view of a power line communication apparatus
in accordance with an embodiment related to a wall-mounted outlet.
Figure 3B is a simplified side view of a power line communication apparatus including
a mains power plug in accordance with an embodiment.
Figure 4 is a simplified flowchart of a method of operating a power line communication
apparatus according to a further embodiment.
[0004] Figure 1 refers to a communications system 100 using a power distribution system
190 for data communication. By way of example, the communications system 100 may be
a power line communications (PLC), mains communications, power line telecommunications
(PLT), broadband power line (BPL) or power band or power line networking (PLN) system
using a modulated carrier superimposed to the 50 or 60 Hz alternating current of the
power lines respectively.
[0005] The communications system 100 is operable as a MIMO (multiple input multiple output)
or MISO (multiple input single output) system with at least a first and a second modem
device 110a, 110b. The first modem device 110a outputs data signals at two or more
first interface ports 101a. The second modem device 110b recovers the data signals
from signals received at three or more second interface ports 101b. The power distribution
system 190 forms the transmission channel connecting the first and second modem devices
110a, 110b. The power distribution system 190 represents a multi-wire connection.
For example, the power distribution system 190 may include power cables comprising
two or more electrical conductors used for transmission of AC electric power (mains)
and for providing earth connection, wherein the power cables may be installed as permanent
wiring within buildings or may be buried in the ground.
[0006] For example, the first modem device 110a may output two differential transmit signals
using the live or phase wire (L, P), the neutral wire (N), and protective earth (PE),
wherein the differential transmit signals are modulated on a carrier superposing the
AC frequency on the mains voltage. The second modem device 110b may receive three
differential receive signals between live wire and neutral wire, between neutral wire
and protective earth, and between live wire and protective earth. According to another
embodiment, the second modem device 110b may receive the three differential receive
signals and a common mode signal resulting from a leakage current from the wiring
as a fourth receive signal. The transmit signals in the transmission channel 190 interfere
with each other through capacitive coupling between the wires such that the first
and second modems may use multi-channel techniques like beamforming for enhancing
transmission throughout.
[0007] One of the first and second modem devices 110a, 110b is a power line communication
apparatus 200 as illustrated in Figure 2. The other modem device 110a, 110b may also
be of the type of the power line communication apparatus 200, another stand-alone
type PLC modem or may be integrated in an electronic device for consumer applications,
for example in a storage unit, a television set, an audio receiver, a video recorder,
or in sensor devices.
[0008] As shown in Figure 2, the power line communication apparatus 200 comprises a mains
power connector assembly 210 with at least three first connectors 211. Each of the
first connectors 211 is adapted to connect the power line communication apparatus
200 to one of the wirings L1, L2, L3, N, PE of a power distribution system. According
to an embodiment the first connectors 211 are terminals, for example clamps or connector
blocks into which the wirings L1, L2, L3, N, PE may be clamped. According to another
embodiment, the mains power connector assembly 210 is a mains power plug where at
least two of the first connectors 211 assigned to live and neutral connections are
pins or prongs. The mains power plug may be a standardized one, for example a mains
power plug in accordance with the CEE 7/4, 7/5, 7/7, NEMA5-nn or SEV1011 standard.
[0009] The power line communication apparatus 200 further includes a mains filter 220 with
at least three first ports 221 and a corresponding number of second ports 222. Each
first port 221 is electrically connected to one of the first connectors 211. According
to an embodiment each first port 221 is directly connected with the corresponding
first connector 211 in a low resistive manner through wires, conductors, and/or clamps.
The mains filter 220 comprises a low-pass filter path between each first port 221
and a corresponding one of the second ports 222.
[0010] An AC power socket (receptacle) 280 comprises at least three second connectors 282,
wherein each second connector 282 is electrically connected to one of the second ports
222 of the mains filter 220. At least two of the second connectors 282 assigned to
live and neutral connections are female connectors. The AC power socket 280 may by
standardized and may comply with any of the CEE 7/4, 7/5, 7/7, NEMA5-nn or SEV1011
standards, by way of example. In case the mains power connector assembly 210 is a
standardized mains power plug, the AC power socket 280 may comply with the same standard.
A power strip or an electric/electronic appliance may be plugged into the AC power
socket to connect an electric/electronic appliance to the mains power distribution
system.
[0011] A power line communication unit 250 is electrically connected with each of the first
connectors 211 and first ports 221, wherein the power line communication unit 250
is configured to transmit and/or receive data according to a transmission method using
more than one wired connection or transmission path between two devices connected
via the power distribution wiring. The power line communication unit 250 includes
a power lines communication modem that may be configured as a receiving device, as
a transmitting device or as bidirectional communication device incorporating the functionalities
of both a receiving and a transmitting device. The power lines communication modem
may be a PLC modem, a mains communications modem, a PLT modem, a BPL modem or a power
band or PLN modem.
[0012] The power line communication apparatus 200 with integrated AC power socket 280 and
mains filter 220 allows the user to easily install or plug a power line modem into
any outlet which is convenient to access for him and without that the outlet is lost
for connecting further electric/electronic appliances. The data signals go directly
from the integrated power line communication unit 250 to the wall outlet and the power
distribution wiring. Neither do they radiate nor are they attenuated by the cable
resistance of a multiple-outlet power strip, which often has to be installed for providing
a sufficient number of outlets for appliances and modems.
[0013] In addition, the mains filter 220 suppresses disturbances and noise from appliances
connected to the AC power socket 280. Since Appliances connected to the filtered AC
power socket 280 cannot cause asymmetry to the mains at the respective outlet, differential
mode MIMO signals of the power line communication unit 250 are not converted into
common mode signals that may radiate from the mains. Hence the system emits less stray
radiation.
[0014] According to an embodiment, at least one of the first connectors 211 of the mains
power connector assembly 210 is an earth (grounding) connection and at least one of
the second connectors 282 of the AC power socket 280 is an earth connection. The filter
paths may differ in their effect on the assigned wired connection. According to an
embodiment each filter path provides interference suppression. For example, each filter
path provides interference suppression to approximately the same degree.
[0015] In accordance with an embodiment, the mains filter 220 includes a low-pass filter
224 which is effective on each of the at least three filter paths. Where one of the
filter paths provides an earth connection, the low-pass filter 224 is also effective
on this filter path approximately to the same degree. For example, the low-pass filter
224 includes filter elements in each of the filter paths, including a filter path
assigned to an earth connection, wherein corresponding filter elements of different
filter paths have the same nominal values such that all at least three filter paths
are configured in the same way. According to an embodiment, the low-pass filter 224
attenuates signal frequencies above 1 MHz, for example in the range between 2 and
30 MHz by at least 3dB, for example 6dB, 10 dB or 20dB. According to an embodiment
the attenuation is at least 50dB. According to other embodiments, the mains filter
220 attenuates another frequency-range above a frequency greater 2 MHz to comply with
the specific frequency range of the powerline communication unit 250.
[0016] The low-pass filter 224 may contain serial filter elements 224a in each filter path.
The serial filter elements 224a may differ from each other. In accordance with an
embodiment, the serial filter elements 224a in each filter path may be elements that
are approximately equivalent to each other with regard to the effect they have. For
example, each serial filter element 224a may be effective as a low-pass filter that
lets pass the 50 Hz or 60 Hz AC frequency and that blocks HF (high frequency) and
VHF (very high frequency). The low-pass filter 224 may provide the same filter degree
and the same cutoff frequencies in each filter path. Each serial filter element 224a
may include one or more inductors, wherein corresponding inductors in different filter
paths may have the same nominal values for inductivity and resistance. The low-pass
filter 224 may also comprise a number of capacitive units 224b, wherein each capacitive
unit 224b is electrically arranged between each pair of filter paths. Each capacitive
unit 224b may provide a parallel filter path with a cutoff frequency defining a pass-band
effective up to at least 50 Hz or 60 Hz and blocking HF and VHF. Each capacitive unit
224b may include one ore more capacitors. According to an embodiment, at 1 MHz each
filter path may provide an attenuation of at least 40 dB. Each capacitive unit 224b
may be connected to a node between two identical inductors of the same filter path,
respectively.
[0017] According to an embodiment the mains filter 220 may also include a common-mode filter
unit 228 to attenuate common mode signals. The common filter unit 228 may include
a common mode choke, a ferrite bead or ring. The common filter unit 228 is effective
on each of the at least three filter paths in the same way and to the same degree.
For example, elements with the same nominal values for inductivity, resistance and
coupling values may be provided in each filter path such that all at least three filter
paths are configured in the same way. Where one of the filter paths provides an earth
connection, the elements are provided in this filter path, too.
[0018] The power line communication apparatus 200 may have four first connectors 211 for
two live connections L1, L2, a neutral connection N and an earth connection, or five
connectors for three live connections L1, L2, L3, a neutral connection N and an earth
connection PE. According to an embodiment, the power plug comprises three first connectors
211 for one live connection L, a neutral connection N and the earth connection PE.
[0019] The power line communication apparatus 200 may further comprise a data outlet 292
connected to the power line communication unit 250, wherein the power line communication
unit 250 outputs data received via the mains power connector assembly 210 at the data
outlet 292 and/or outputs data received via the data outlet 292 at the mains power
connector assembly 210. The data outlet 292 may be a standardized one, for example
according to the USB, Ethernet, Firewire or any other wired communication standard.
[0020] Alternatively or in addition, the power line communication apparatus 200 may comprise
a wireless modem 294 connected to the power line communication unit 250, wherein the
power line communication unit 250 outputs data received via the mains power connector
assembly 210 via the wireless modem 294 and/or outputs data received via the wireless
modem 294 via the mains power connector assembly 210. The wireless modem may be a
standardized one and may comply with the IEEE 802.11 standard by way of example.
[0021] Figure 3A shows an on-wall or in-wall mounted power line communication apparatus
200 with an AC power socket 280, which may be a CEE 7/7 socket, and a data outlet
292, which may be a female modular connector, like a 8P8C jack (socket). Terminals
at the backside oriented to the wall side provide interfaces to the power distribution
wiring.
[0022] Figure 3B shows a plug-in power line communication apparatus 200 with an AC power
socket 280, a data outlet 292, and a mains power plug 210a, which may be CEE 7/7 plug,
by way of example.
[0023] Figure 4 refers to a method of operating a power line communication apparatus. AC
electric current is supplied to an electric appliance connected to an AC power socket
using at least three mains connections (402). The at least three mains connections
may provide two live connections and a neutral connection. According to an embodiment
one of the at least three mains connections provides an earth connection. Noise and
disturbances output by the electric appliance at the mains connections are low-pass
filtered using a mains filter effective on each of the at least three mains connections
(404) in the same way. According to an embodiment, each low-pass filter path of the
mains filter provides interference suppression. The mains filter has a mains side
oriented to the mains and an appliance side oriented to the AC power socket. A power
line communication unit that is connected to the mains side of the mains filter is
operated in a MIMO or MISO mode (406). The mains filter attenuates signal frequencies
in the range used by the powerline communication unit and may attenuate common mode
signals.
1. A power line communication apparatus comprising:
a mains power connector assembly (210) comprising at least three first connectors
(211);
a mains filter (220) with at least three first ports (221), at least three second
ports (222) and at least three filter paths, wherein each first port (221) is electrically
connected to one of the first connectors (211) and each filter path is provided between
one of the first and one of the second ports (221, 222);
an AC power socket (280) comprising at least three second connectors (282), wherein
each second connector (282) is electrically connected to one of the second ports (222);
a power line communication unit (250) electrically connected with each of the first
ports (221), wherein the power line communication unit (250) is configured to transmit
and/or receive data according to a transmission method using more than one transmission
channel between two devices connected via a power line wiring.
2. The power line communication apparatus of claim 1, wherein
the mains power connector assembly (210) is a mains power plug (210a).
3. The power line communication apparatus of any of claims 1 or 2, wherein
one of the first connectors (211) and one of the second connectors (282) are suitable
for earth connections.
4. The power line communication apparatus of any of claims 1 to 3, wherein
the mains filter (220) comprises a low-pass filter (224) effective on each of the
at least three filter paths in the same way such that all at least three filter paths
are configured in the same way.
5. The power line communication apparatus of any of claims 1 to 4, wherein
the low-pass filter (224) is arranged to provide the same degree of interference suppression
in each of the at least three filter paths.
6. The power line communication apparatus of any of claims 1 to 5, wherein
the low-pass filter (224) comprises serial filter elements (224a) in each filter path,
the serial filter elements (224a) being inductors, wherein corresponding inductors
in the filter paths have the same inductivity and resistance.
7. The power line communication apparatus of any of claims 1 to 6, wherein
the low-pass filter (224) comprises a capacitive unit (224b) between each pair of
the at least three filter paths.
8. The power line communication apparatus of any of claims 1 to 7, wherein
at 1 MHz each filter path provides the same attenuation of at least 50 dB.
9. The power line communication apparatus of any of claims 1 to 8, wherein
the mains filter (220) comprises a common-mode filter unit (228) effective on each
of the at least three filter paths.
10. The power line communication apparatus of any of claims 1 to 9, wherein
the main power connector assembly (210) comprises not more than three first connectors
(211).
11. The power line communication apparatus of any of claims 1 to 10, further comprising
a data outlet (292) connected to the power line communication unit (250), the power
line communication unit (250) configured to output data received via the mains power
connector assembly (210) at the data outlet (292) and/or to output data received via
the data outlet (292) at the mains power connector assembly (210).
12. The power line communication apparatus of any of claims 1 to 11, further comprising
a wireless modem (294) connected to the power line communication unit (250), the power
line communication unit (250) configured to output data received via the mains power
connector assembly (210) through the wireless modem (294) and/or to output data received
via the wireless modem (294) at the mains power connector assembly (210).
13. A power line communications system comprising the power line communication apparatus
of any of the preceding claims.
14. A method of operating a power line communication apparatus, the method comprising
supplying AC electric current to an electric appliance connected to an AC power socket
(280) using at least three mains connections,
filtering noise and disturbances output by the electric appliance at the at least
three mains connections with a mains filter (220) effective on each of the at least
three mains connections, the mains filter (220) having a mains side oriented to the
mains and an appliance side oriented to the AC power socket (280);
operating, in a MIMO or MISO mode, a power line communication unit (250) connected
to the mains filter (220) at the mains side,
15. The method of claim 15, wherein
the mains filter (220) is effective on each of the at least three mains connections
in the same way.
16. The method of any of claims 14 or 15, wherein
one of the mains connections provides an earth connection.
17. A power line communication apparatus comprising:
mains connector means comprising at least three first connectors;
filter means with at least three first ports, each first port connected to one of
the first connectors, and with at least three second ports, each second port connected
to one of the first ports via a low-pass filter path;
receptacle means comprising at least three second connectors, each second connector
electrically connected to one of the second ports;
power line communication means electrically connected with each of the first connectors
and first ports, wherein the power line communication means is configured to transmit
and/or receive data according to a transmission method using more than one transmission
channel between two devices connected via a power line wiring.